arch/blackfin/mach-bf561/coreb.c

   1 /* Load firmware into Core B on a BF561
   2  *
   3  * Author: Bas Vermeulen <bvermeul@blackstar.xs4all.nl>
   4  *
   5  * Copyright 2004-2009 Analog Devices Inc.
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 /* The Core B reset func requires code in the application that is loaded into
  10  * Core B.  In order to reset, the application needs to install an interrupt
  11  * handler for Supplemental Interrupt 0, that sets RETI to 0xff600000 and
  12  * writes bit 11 of SICB_SYSCR when bit 5 of SICA_SYSCR is 0.  This causes Core
  13  * B to stall when Supplemental Interrupt 0 is set, and will reset PC to
  14  * 0xff600000 when COREB_SRAM_INIT is cleared.
  15  */
  16
  17 #include <linux/device.h>
  18 #include <linux/fs.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/miscdevice.h>
  22
  23 #define CMD_COREB_START         _IO('b', 0)
  24 #define CMD_COREB_STOP          _IO('b', 1)
  25 #define CMD_COREB_RESET         _IO('b', 2)
  26
  27 static long
  28 coreb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
  29 {
  30         int ret = 0;
  31
  32         switch (cmd) {
  33         case CMD_COREB_START:
  34                 bfin_write_SYSCR(bfin_read_SYSCR() & ~0x0020);
  35                 break;
  36         case CMD_COREB_STOP:
  37                 bfin_write_SYSCR(bfin_read_SYSCR() | 0x0020);
  38                 bfin_write_SICB_SYSCR(bfin_read_SICB_SYSCR() | 0x0080);
  39                 break;
  40         case CMD_COREB_RESET:
  41                 bfin_write_SICB_SYSCR(bfin_read_SICB_SYSCR() | 0x0080);
  42                 break;
  43         default:
  44                 ret = -EINVAL;
  45                 break;
  46         }
  47
  48         CSYNC();
  49
  50         return ret;
  51 }
  52
  53 static const struct file_operations coreb_fops = {
  54         .owner          = THIS_MODULE,
  55         .unlocked_ioctl = coreb_ioctl,
  56         .llseek         = noop_llseek,
  57 };
  58
  59 static struct miscdevice coreb_dev = {
  60         .minor = MISC_DYNAMIC_MINOR,
  61         .name  = "coreb",
  62         .fops  = &coreb_fops,
  63 };
  64 builtin_misc_device(coreb_dev);